As the earth resources are wasted and the technology is developed, the shortage of the international energy resources is induced. In view of this, various countries in the world positively invest in the development of various alternative sources of energy. Among the alternative sources of energy, because sunlight is inexhaustible in supply and always available for use, it pays close attention to the development of solar energy apparatus for generating electric power, such as a solar cell.
A solar cell is a renewable energy that can directly generate electric power by the interaction of the sunlight and semiconductor materials. The solar cell will not discharge any gas, which includes SiO2, so that the solar cell is a green power without pollution and can improve the problem of the earth's greenhouse effect.
The solar cell directly absorbs sunlight to generate electric power by using the photoelectric effect of the semiconductor. The principle of generating electric power of the solar cell is that when the sunlight irradiates the solar cell, the solar cell absorbs the energy from the sunlight to make a p-type semiconductor and an n-type semiconductor of the solar cell respectively generate electrons and holes, and to separate the electrons and the holes to form a voltage drop to generate current.
In order to increase the light-absorbing ability of the solar cell, a current method is to modify the design of a solar concentrator of the solar cell. Refer to FIG. 1A. FIG. 1A is a schematic diagram showing the collecting of light of a conventional solar concentrator. An entire surface 102 of a conventional solar concentrator 100 is set with a plurality of trenches 104. When the sun irradiates the surface 102 of the solar concentrator 100, the incident sunlight 108 can be guided downward by the trenches 104 to increase the energy absorptivity for the sunlight 108.
However, as shown in FIG. 1B, when the sunlight 108 is at a low angle relative to the surface 102 of the solar concentrator 100, the sunlight 108 cannot be effectively guided downward by the trenches 108 of the surface 102 of the solar concentrator 100. Therefore, when the sunlight 108 is at a low angle, the conventional solar concentrator 100 cannot achieve a good light-collecting effect.
Therefore, as the shortage of the energy resources is induced, a solar concentrator having a high light-collecting effect is needed to increase the light-absorbing efficiency of a solar cell for the energy of the sunlight.